Semiconductor structure having a barrier layer comprising aluminum nitride single crystal and method for growing the same

Abstract

The application discloses a semiconductor structure with a barrier layer containing aluminum nitride monocrystal and a growth method thereof, and belongs to the technical field of semiconductors, and comprises a substrate, a buffer layer, a GaN channel layer and an aluminum nitride monocrystal barrier layer which are sequentially stacked; a heterojunction comprises the GaN channel layer and the aluminum nitride monocrystal barrier layer; the aluminum nitride monocrystal barrier layer is provided with periodically stacked AlN ultra-thin quantum wells; a proportional relationship between a first vertical distance of the AlN ultra-thin quantum wells from a gate and a second vertical distance of the AlN ultra-thin quantum wells from the GaN channel layer conforms to quantum mechanical tunneling effect and semiconductor polarization field theory; the AlN ultra-thin quantum wells comprise a plurality of quantum well units, each quantum well unit comprises an AlN thin layer and an Al0.5Ga0.5N thin layer which are stacked, and a stacking period of the AlN ultra-thin quantum wells is less than 5; and a two-dimensional electron gas is formed in the GaN channel layer.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor, and particularly relates to a semiconductor structure with a barrier layer containing aluminum nitride single crystal and a growth method thereof. BACKGROUND

[0002] The aluminum nitride single crystal barrier layer is a key functional layer in a semiconductor heterojunction structure designed based on aluminum nitride single crystal material, and its core role is to optimize device performance through polarization effect and high barrier characteristics. The semiconductor structure plays an irreplaceable role in modern electronic and electrical engineering. It determines the performance of the device, including response speed, power consumption, thermal management, etc. Efficient semiconductor structures can support high-frequency, high-power applications and are suitable for computers, communication devices, sensors and other fields. Moreover, the selection of semiconductor materials and structures has a significant impact on power efficiency, operating temperature range and device reliability, so the optimization of semiconductor structures is crucial in the design of efficient electronic devices.

[0003] However, existing semiconductors have low heterojunction bandgap differences, which leads to non-ideal effects when electrons or holes cross the bandgap under high electric field and high frequency operation. Carriers may leak or scatter, reducing the switching efficiency and stability of the device. In high-power applications, this situation is easily affected by thermal effects and power loss, limiting its performance and reliability in high-frequency, high-power scenarios. SUMMARY

[0004] To solve the problem of the existing semiconductor in the prior art due to the low heterojunction bandgap difference, which leads to non-ideal effects when electrons or holes cross the bandgap under high electric field and high frequency operation. Carriers may leak or scatter, reducing the switching efficiency and stability of the device. In high-power applications, this situation is easily affected by thermal effects and power loss, limiting its performance and reliability in high-frequency, high-power scenarios, which seriously affects the high-frequency performance of the device. Technical problems, the present application provides a semiconductor structure with a barrier layer containing aluminum nitride single crystal and a growth method thereof.

[0005] First aspect

[0006] The present application provides a semiconductor structure with a barrier layer containing aluminum nitride single crystal, comprising: a substrate, a buffer layer, a heterojunction, a source electrode, a gate electrode and a drain electrode;

[0007] The heterojunction comprises a GaN channel layer and an aluminum nitride single crystal barrier layer;

[0008] The substrate, the buffer layer, the GaN channel layer and the aluminum nitride single crystal barrier layer are sequentially laminated;

[0009] The source electrode and the drain electrode are both in contact with the GaN channel layer;

[0010] The gate is in contact with the aluminum nitride single crystal barrier layer;

[0011] The aluminum nitride single crystal barrier layer is provided with periodically stacked AlN ultra-thin quantum wells, and the ratio between the first vertical distance of the AlN ultra-thin quantum well from the gate and the second vertical distance of the AlN ultra-thin quantum well from the GaN channel layer conforms to the quantum mechanical tunneling effect and the semiconductor polarization field theory.

[0012] The AlN ultra-thin quantum well includes a plurality of quantum well units, and each quantum well unit includes an AlN thin layer and an Al 0.5 Ga 0.5 N thin layer arranged in a stack, and the stacking period of the AlN ultra-thin quantum well is less than 5;

[0013] Under the polarization effect of the heterojunction, a two-dimensional electron gas is formed in the GaN channel layer to provide a conductive channel.

[0014] The second aspect

[0015] The present application provides a growth method of a semiconductor structure having a barrier layer containing an aluminum nitride single crystal, and the method comprises:

[0016] S1: pretreating a substrate in a MOCVD cavity;

[0017] S2: growing a buffer layer on the pretreated substrate;

[0018] S3: adjusting the temperature to 1080℃, the TMG flow rate is 100 μmol / min, and the GaN channel layer is grown at a growth rate of 1.2 μm / h;

[0019] S4: growing the aluminum nitride single crystal barrier layer at a gradient temperature according to the ratio between the first vertical distance and the second vertical distance;

[0020] S5: adjusting the temperature to 900℃, switching the TMA flow rate and the TMG flow rate according to a periodic stacking rule to grow the AlN ultra-thin quantum well, wherein the temperature is adjusted to 700℃ in a nitrogen environment at the end of each stacking period for a preset length of time;

[0021] S6: growing the remaining thickness of the aluminum nitride single crystal barrier layer at a gradient temperature;

[0022] S7: growing the source electrode, the gate electrode and the drain electrode respectively to obtain the semiconductor structure.

[0023] Compared with the prior art, the present application has at least the following beneficial technical effects:

[0024] In the embodiments of the present application, the combination of the aluminum nitride single crystal barrier layer and the GaN channel layer efficiently utilizes the wide bandgap characteristics of aluminum nitride, improves the heterojunction bandgap difference, optimizes the electron transmission channel, and improves the conductivity performance, thereby effectively enhancing the isolation of electrons at the heterojunction interface, reducing the leakage and scattering of carriers, forming a high-efficiency two-dimensional electron gas, and improving the switching efficiency and stability of the device. Secondly, the periodic stacking of AlN ultra-thin quantum wells in the aluminum nitride single crystal barrier layer optimizes the quantum mechanical tunneling effect and the semiconductor polarization field theory, accurately controls the electron behavior, and reduces the non-ideal effects caused by the bandgap difference. At the same time, the structural design of the AlN ultra-thin quantum well reduces the carrier scattering, effectively reduces the power loss, and improves the thermal management performance, thereby enhancing the reliability and stability of the device in high-frequency and high-power applications. Therefore, the semiconductor structure has stronger performance advantages in the high-frequency and high-power fields, and is suitable for a wider range of high-performance electronic device applications. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above-mentioned characteristics, technical features, advantages and implementation modes of the present application will be further described in a clear and understandable manner in combination with the preferred embodiments and the accompanying drawings.

[0026] Figure 1 is a structural schematic diagram of a semiconductor structure with a barrier layer containing an aluminum nitride single crystal provided by the present application;

[0027] Figure 2 is a structural schematic diagram of a heterojunction provided by the present application;

[0028] Figure 3 is a structural schematic diagram of an AlN ultra-thin quantum well provided by the present application;

[0029] Figure 4 is a structural schematic diagram of a T-shaped gate provided by the present application;

[0030] Figure 5 is a flowchart of a growth method of a semiconductor structure with a barrier layer containing an aluminum nitride single crystal provided by the present application. DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the specific implementation modes of the present application will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0032] Embodiment 1

[0033] In one embodiment, reference is made to the accompanying drawingsFigure 1 , shows the structure diagram of the semiconductor structure provided by the application with the barrier layer containing aluminum nitride single crystal. Referring to the description accompanying drawings Figure 2 , shows the structure diagram of the heterojunction provided by the application. Figure 1 and Figure 2 The semiconductor structure is shown in the figure, which includes a source, a gate and a drain, and the hierarchical structure is stacked in a specific order. The core is a GaN (gallium nitride) channel layer, which provides a conductive channel for electrons. Above the GaN channel layer is an aluminum nitride (AlN) single crystal barrier layer, which helps to isolate the channel layer and prevent carrier leakage. The AlN layer is provided with periodically stacked quantum wells (consisting of alternating AlN and Al0.5Ga0.5N thin layers), which optimize carrier behavior through quantum effects and reduce carrier scattering, thereby improving the performance of the device. The structure utilizes the heterojunction polarization effect between GaN and AlN to form a high-density two-dimensional electron gas (2DEG) in the GaN channel layer, further enhancing conductivity and device performance, especially suitable for high-frequency and high-power applications.

[0034] Referring to the description accompanying drawings Figure 3 , shows the structure diagram of the AlN ultra-thin quantum well provided by the application.

[0035] Figure 3 The periodically stacked AlN ultra-thin quantum well is shown in the figure, which shows the periodically stacked AlN ultra-thin quantum well. Each layer includes alternating AlN thin layers and Al0.5Ga0.5N thin layers. By alternating these materials, a thin layer structure with quantum confinement effect is formed, thereby controlling the behavior of electrons on a quantum scale. The AlN thin layer has a wider band gap, which can effectively isolate the carriers, while the Al0.5Ga0.5N thin layer helps to adjust the electronic properties of the quantum well. The design of periodic stacking can improve the quantum effect, improve the conductivity of the carrier and the overall performance of the device.

[0036] The semiconductor structure provided by the application with the barrier layer containing aluminum nitride single crystal includes: a substrate, a buffer layer, a heterojunction, a source, a gate and a drain.

[0037] Among them, the heterojunction refers to the interface structure composed of two different semiconductor materials (such as GaN and aluminum nitride). Because of their different band gaps, the formed heterojunction can control the flow and distribution of carriers, thereby affecting the performance of the semiconductor device.

[0038] The heterojunction includes a GaN channel layer and an aluminum nitride single crystal barrier layer.

[0039] The substrate, the buffer layer, the GaN channel layer and the aluminum nitride single crystal barrier layer are sequentially laminated.

[0040] The source electrode and the drain electrode are both arranged in contact with the GaN channel layer.

[0041] The gate electrode is arranged in contact with the aluminum nitride single crystal barrier layer.

[0042] The aluminum nitride single crystal barrier layer is provided with periodically stacked AlN ultra-thin quantum wells, and the ratio between the first vertical distance of the AlN ultra-thin quantum well from the gate electrode and the second vertical distance from the GaN channel layer conforms to the quantum mechanical tunneling effect and the semiconductor polarization field theory.

[0043] The AlN ultra-thin quantum well is a very thin quantum structure formed by alternating deposition of aluminum nitride (AlN) and other semiconductor materials (such as Al0.5Ga0.5N). The quantum well is characterized by the confinement of electrons within a very narrow region, typically a few nanometers thick, so that the behavior of the electrons exhibits quantum mechanical effects. AlN as a quantum well material has a wide band gap, which means it can effectively isolate carriers, reduce carrier scattering, and enhance carrier stability. By setting the AlN ultra-thin quantum well, the transmission path of the carriers can be optimized, the electron mobility can be improved, and efficient current transmission can be achieved. This structure plays an important role in improving the performance of semiconductor devices in high-frequency, high-power and other applications.

[0044] It can be understood that the tunneling effect is a quantum mechanical effect, when electrons or other particles face an energy barrier that seems impossible to cross, they can still cross the barrier, resulting in the transmission of electron flow. The polarization field theory is an electric field effect caused by the band gap difference of the heterojunction, which helps to form a high-density carrier at the interface and improve the conductivity of the device.

[0045] It should be noted that this structure sets the periodically stacked AlN ultra-thin quantum well in the aluminum nitride single crystal barrier layer, and uses precise design to control the distance ratio between the gate electrode and the GaN channel layer. This ratio conforms to the quantum mechanical tunneling effect and the semiconductor polarization field theory, thereby optimizing the transmission path of the electrons, improving the formation efficiency of the two-dimensional electron gas, reducing the carrier scattering and leakage, and improving the conductivity and stability of the device. Through this design, the performance of the device can be effectively improved in high-frequency and high-power applications.

[0046] The AlN ultra-thin quantum well includes a plurality of quantum well units, each quantum well unit includes an AlN thin layer and an Al 0.5 Ga 0.5 N thin layer arranged in a stack, and the stacking period of the AlN ultra-thin quantum well is less than 5.

[0047] Among them, the stacking period value of the AlN ultra-thin quantum well is 3, 4 or 5. The AlN ultra-thin quantum well in this structure is composed of multiple quantum well units, each of which contains alternating stacked AlN thin layers and Al0.5Ga0.5N thin layers. This alternating stacking design optimizes the carrier transport characteristics by adjusting the band gap differences of different materials. A stacking period of less than 5 means that the number of stacked layers of these quantum well units is small, thereby reducing the complexity of the material while ensuring a strong expression of the quantum effect, effectively improving the electron transport efficiency and overall performance of the device.

[0048] Under the polarization effect of the heterojunction, a two-dimensional electron gas is formed in the GaN channel layer to provide a conductive channel.

[0049] Among them, two-dimensional electron gas refers to a two-dimensional electron conduction channel formed at the heterojunction interface due to polarization effect or quantum effect. The movement of electrons in this channel is limited to two planar dimensions, which greatly improves the current transmission capacity.

[0050] It should be noted that the semiconductor structure utilizes the heterojunction effect between the aluminum nitride single crystal barrier layer and the GaN channel layer to optimize the electron conduction channel. In this structure, periodically stacked AlN ultra-thin quantum wells are set within the aluminum nitride single crystal barrier layer. These quantum wells are precisely designed to control the distance between the gate and the GaN channel layer. By utilizing the quantum mechanical tunneling effect and semiconductor polarization field theory, electrons form an efficient conductive channel in the two-dimensional electron gas. Due to the wide bandgap characteristics of aluminum nitride, the carrier isolation effect at the interface is enhanced, carrier leakage and scattering are reduced, and the switching speed and stability of the device are improved. At the same time, the quantum well structure reduces energy loss and scattering effects, optimizes thermal management, and enhances the performance of the device in high-frequency, high-power applications. Therefore, this structure has higher power density, better thermal conductivity and stronger anti-scattering ability, and is suitable for a wider range of high-efficiency electronic devices.

[0051] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0052] In the embodiment of the present application, the combination of the aluminum nitride single crystal barrier layer and the GaN channel layer makes efficient use of the wide bandgap characteristics of aluminum nitride, improves the heterojunction bandgap difference, optimizes the electron transport channel, and improves the electrical conductivity, thereby effectively enhancing the isolation of electrons at the heterojunction interface, reducing the leakage and scattering of carriers, forming a high-efficiency two-dimensional electron gas, and thus improving the switching efficiency and stability of the device. Secondly, the periodic stacking of AlN ultra-thin quantum wells in the aluminum nitride single crystal barrier layer optimizes the quantum mechanical tunneling effect and the semiconductor polarization field theory, accurately controls the electron behavior, and reduces the non-ideal effects caused by the bandgap difference. At the same time, the structural design of the AlN ultra-thin quantum well reduces the carrier scattering, effectively reduces the power loss, and improves the thermal management performance, thereby enhancing the reliability and stability of the device in high-frequency and high-power applications. Therefore, the semiconductor structure has stronger performance advantages in the high-frequency and high-power fields, and is suitable for a wider range of high-performance electronic device applications.

[0053] In a possible implementation, the substrate includes a Si substrate and a sapphire substrate.

[0054] It should be noted that the substrate can be selected as a Si (silicon) substrate or a sapphire substrate. The Si substrate has a lower cost and a wide range of applications, and is suitable for mass production. The sapphire substrate has better thermal conductivity and higher high-temperature resistance, and is suitable for high-power and high-frequency device applications, which can improve the stability and performance of the device.

[0055] In a possible implementation, the buffer layer is an AlGaN buffer layer.

[0056] It should be noted that the AlGaN buffer layer can effectively alleviate the lattice mismatch problem between the substrate and the GaN layer, reduce stress, avoid crack generation, and improve the quality of the GaN layer. At the same time, AlGaN has good thermal conductivity, which is helpful for heat dissipation of the device and improves the performance and reliability in high-frequency and high-power applications.

[0057] In a possible implementation, the ratio between the thickness of the AlN thin layer and the thickness of the Al0.5Ga0.5N thin layer is 5:3. 0.5 Ga 0.5 N thin layer is 5:3. This ratio helps to optimize the electronic properties of the quantum well and ensure the best performance of the quantum effect. By adjusting the ratio of the two materials, the carrier transport and scattering characteristics can be effectively controlled, and the performance and stability of the device can be improved, especially in high-frequency and high-power applications.

[0058] It should be noted that the ratio of the thickness of the AlN thin layer to the thickness of the Al0.5Ga0.5N thin layer is 5:3. This ratio helps to optimize the electronic properties of the quantum well and ensure the best performance of the quantum effect. By adjusting the ratio of the two materials, the carrier transport and scattering characteristics can be effectively controlled, and the performance and stability of the device can be improved, especially in high-frequency and high-power applications.

[0059] wherein the specific value of the Thomas-Fermi screening length is 25 nm. Optionally, α can take any value in the range [ 0 . 5 , 1 . 2 ] Any value within, such as 0.6. , represents the free electron mass.

[0060] Specifically, the calculation of the proportional relationship between the first vertical distance (d1) and the second vertical distance (d2) helps to optimize the electric field distribution between the gate and the aluminum nitride single crystal barrier layer. Through this proportional relationship, the electric field intensity between the aluminum nitride single crystal barrier layer and the GaN channel layer can be controlled, so as to accurately adjust the formation of the two-dimensional electron gas (2DEG). This proportional relationship combines the quantum mechanical tunneling effect and the semiconductor polarization field theory, which can reduce carrier leakage and scattering, ensure the efficient and stable electron transmission path. In addition, this design can optimize the thermal management and power loss of the device in high-frequency and high-power applications, reduce the leakage current, improve the switching efficiency and long-term reliability of the device. By accurately calculating the ratio of d1 and d2, the performance of the device can be maximized in design, especially for high-frequency and high-power electronic devices, to ensure its high efficiency and stability in practical application.

[0061] Specifically, the actual heterojunction interface is not an ideal abrupt change, but there is a transition region with gradual change of material composition. That is, the thickness of this transition region affects the formation and performance of 2DEG. If the transition layer is too thick, it may weaken the polarization effect and affect the electron concentration and mobility. The heterojunction thickness plays a key role in semiconductor devices, as it determines the interface characteristics between different materials and affects the migration and scattering of carriers. By reasonably calculating the ratio of the AlN ultra-thin quantum well and the heterojunction thickness, the behavior of electrons in the interface region can be accurately controlled, and the formation of the two-dimensional electron gas (2DEG) can be optimized. Combined with the calculation of the heterojunction thickness, the full play of the quantum effect can be ensured, and the thickness of the transition layer can be controlled, thereby reducing the electric field shielding effect, improving the carrier mobility, and maximizing the stability and efficiency of the device.

[0062] Referring to the drawings attached to the specification Figure 4 , a structure schematic diagram of the T-shaped gate provided by the present application is shown.

[0063] Figure 4 The structure of the T-shaped gate in the present application is shown. In this embodiment, a rectangular aluminum nitride cover layer is arranged between the T-shaped gate and the aluminum nitride single crystal barrier layer. The thickness of the cover layer is less than the first vertical distance between the gate and the GaN channel layer. The width and length of the rectangular aluminum nitride cover layer are the same as those of the gate, which can effectively enhance the control ability of the gate and optimize the electric field distribution, reducing the carrier leakage. Through this design, the leakage current can be effectively reduced, the switching efficiency and stability of the device can be improved, and the performance of the semiconductor device in high-frequency and high-power applications can be enhanced.

[0064] In one possible implementation, the gate is a T-shaped gate.

[0065] A rectangular AlN capping layer is provided between the T-shaped gate and the AlN single-crystal barrier layer, wherein the thickness of the rectangular AlN capping layer is less than the first vertical distance, and the width and length of the rectangular AlN capping layer are the same as those of the gate.

[0066] The gate foot is a finger-shaped structure in the gate design, which enhances the control ability of the gate by contacting the AlN layer, thereby optimizing the electric field distribution and reducing the carrier leakage. This design helps to improve the performance of the device, especially enhances the control of the two-dimensional electron gas (2DEG), reduces the power loss, and improves the switching efficiency.

[0067] It should be noted that the rectangular AlN capping layer between the T-shaped gate and the AlN single-crystal barrier layer can effectively enhance the gate control ability. The thickness of the capping layer is less than the vertical distance between the gate and the GaN channel layer, and the width and length of the capping layer are the same as those of the gate. Through this design, the potential barrier under the gate is locally thickened, which can effectively reduce the leakage current, reduce the power loss and improve the stability of the device. At the same time, the drift of threshold voltage (Vth) is less than 0.1V, which ensures high precision control in long-term operation.

[0068] Specifically, the semiconductor structure containing the AlN single-crystal barrier layer significantly improves the performance in high-frequency and high-power applications by combining the GaN channel layer and the AlN barrier layer. The AlN single-crystal barrier layer effectively prevents carrier leakage and optimizes electron behavior through periodically stacked AlN ultra-thin quantum wells, reducing scattering and improving conductivity. The structure utilizes the heterojunction polarization effect between GaN and AlN to form a high-density two-dimensional electron gas (2DEG), enhancing the conductivity and stability of the device. By precisely regulating the distance between the gate and the AlN barrier layer and the quantum effect, the electron mobility can be improved, the power loss can be reduced, and the thermal management can be optimized. In addition, the combination of the T-shaped gate design and the rectangular AlN capping layer further improves the control ability of the gate, reduces the leakage current, and ensures long-term stability and high-precision control.

[0069] Example 2

[0070] In one embodiment, referring to the flowchart of the growth method of the semiconductor structure provided by the present application shown in the accompanying drawings of the specification, Figure 5 , the growth method of the semiconductor structure provided by the present application having a barrier layer containing an AlN single crystal includes the following steps.

[0071] The growth method of the semiconductor structure provided by the present application having a barrier layer containing an AlN single crystal includes the following steps.

[0072] S1: Pre-treat the substrate in the MOCVD cavity.

[0073] Specifically, the pretreatment process is as follows: first, acetone / isopropanol ultrasonic cleaning (10 min). Then, HF:H2O=1:10 solution etching for 30 seconds (remove oxide layer). Finally, after nitrogen blowing at 120℃, in-situ annealing at 1200℃ for 30 minutes.

[0074] S2: growing a buffer layer on the pretreated substrate.

[0075] S3: adjusting the temperature to 1080℃, TMG flow rate of 100μmol / min, growing GaN channel layer at a growth rate of 1.2 μm / h.

[0076] TMG (Trimethylgallium) is an organic gallium compound commonly used in metal organic chemical vapor deposition (MOCVD) processes as a gallium source for synthesizing GaN, GaAs, and other compound semiconductor materials. In step S3, the temperature is adjusted to 1080℃, and a TMG flow rate of 100μmol / min is used for the growth of the GaN channel layer. In this process, metal organic chemical vapor deposition (MOCVD) technology is used to deposit the GaN channel layer at a growth rate of 1.2 μm / h. This temperature and flow rate setting helps to ensure high-quality deposition of the GaN layer, controlling the growth rate to achieve the desired film thickness and uniformity.

[0077] S4: growing an aluminum nitride single crystal barrier layer with a gradual temperature change according to a proportional relationship between the first vertical distance and the second vertical distance.

[0078] In one possible implementation, S4 is specifically: adjusting the temperature to 850℃, growing a first pre-set thickness of aluminum nitride single crystal barrier layer. Adjusting the temperature to 950℃, growing a second pre-set thickness of aluminum nitride single crystal barrier layer, wherein the proportional relationship between the first pre-set thickness and the second pre-set thickness is 1:6.

[0079] It should be noted that first, the temperature is adjusted to 850℃, and a first pre-set thickness of aluminum nitride single crystal barrier layer is grown. Then, the temperature is increased to 950℃, and a second pre-set thickness of aluminum nitride single crystal barrier layer is grown, and the thickness ratio of the two layers is 1:6. This gradual temperature growth strategy can optimize the quality and performance of the aluminum nitride single crystal barrier layer. By adjusting the growth temperature and thickness ratio, the lattice matching and stress distribution between layers can be effectively controlled, thereby improving the stability and conductivity of the device, and also helping to achieve the ideal two-dimensional electron gas (2DEG) structure.

[0080] S5: adjusting the temperature to 900℃, switching the TMA flow rate and TMG flow rate according to the periodic stacking rule, growing AlN ultra-thin quantum well, wherein at the end of each stacking period, the temperature is adjusted to 700℃ in a nitrogen environment for a pre-set annealing time.

[0081] Among them, TMA (trimethylaluminum) is an organoaluminum compound widely used as an aluminum source material in metal-organic chemical vapor deposition (MOCVD) processes. TMA decomposes at high temperatures and releases aluminum atoms, which react with a nitrogen source to form aluminum nitride (AlN) or other aluminum-based materials. Due to its high reactivity, TMA is commonly used to grow materials such as AlN and AlGaN, particularly in semiconductor devices and quantum structures, where it effectively controls the thickness and quality of thin films. In step S5, the temperature is adjusted to 900°C, and the flow rates of TMA (organoaluminum) and TMG (organogallium) are switched according to a periodic stacking pattern to grow ultra-thin AlN quantum wells. After each stacking cycle, the temperature is lowered to 700°C in a nitrogen atmosphere and an in-situ annealing process is performed for a predetermined period. This process helps optimize the quantum well structure, enhance the quantum effect, and improve the electronic properties of the material. The annealing also helps remove internal stress and improve film quality.

[0082] It should be noted that those skilled in the art can set the preset time length according to actual needs, and the present invention does not limit this. Optionally, the preset time length can be set to 60s.

[0083] S6: Grow the remaining thickness of the aluminum nitride single crystal barrier layer at a gradual temperature.

[0084] S7: Grow the source, gate and drain separately to obtain a semiconductor structure.

[0085] In a possible implementation manner, the post-treatment process of the aluminum nitride single crystal barrier layer is: annealing the aluminum nitride single crystal barrier layer at 1400° C. in a nitrogen environment.

[0086] It should be noted that the post-treatment process for the aluminum nitride single crystal barrier layer is to anneal it at a high temperature of 1400°C in a nitrogen environment. This annealing process helps remove stress, defects, and inhomogeneities within the aluminum nitride layer, promoting crystal rearrangement and improving quality. This high-temperature annealing can significantly improve the crystal structure of the aluminum nitride single crystal barrier layer, enhancing its conductivity and stability, and ensuring the reliability and efficiency of the device in high-frequency, high-power applications.

[0087] In practical applications, this growth method has the advantage of precisely controlling the growth process of each layer, optimizing the quality and performance of aluminum nitride single crystal barrier layers, GaN channel layers, and AlN ultra-thin quantum wells by gradually adjusting the temperature and flow. Through gradual temperature control and periodic stacking, the lattice matching and stress distribution of each layer can be effectively adjusted to ensure high-quality bonding between layers, reduce defects and unevenness. In addition, through timely in-situ annealing and high-temperature annealing, stress can be removed and film quality can be improved, thereby improving the conductivity, stability and reliability of the device, especially in high-frequency and high-power applications, showing higher performance and enhancing the long-term stability and efficiency of the device.

[0088] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered within the scope of the present disclosure.

[0089] The above embodiments only express several implementation manners of the present application, and the description is specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A semiconductor structure having a barrier layer comprising a single crystal of aluminum nitride, characterized in that, The semiconductor structure comprises a substrate, a buffer layer, a heterojunction, a source electrode, a gate electrode and a drain electrode. The heterojunction comprises a GaN channel layer and an aluminum nitride single-crystal barrier layer. The substrate, the buffer layer, the GaN channel layer and the aluminum nitride single-crystal barrier layer are sequentially stacked. The source electrode and the drain electrode are both in contact with the GaN channel layer. The gate electrode is in contact with the aluminum nitride single-crystal barrier layer. The aluminum nitride single-crystal barrier layer is provided with periodically stacked AlN ultra-thin quantum wells, and the ratio between the first vertical distance from the gate electrode and the second vertical distance from the GaN channel layer meets the quantum mechanical tunneling effect and the semiconductor polarization field theory. Under the polarization effect of the heterojunction, a two-dimensional electron gas is formed in the GaN channel layer to provide a conductive channel. The AlN ultra-thin quantum well comprises a plurality of quantum well units, each quantum well unit comprising AlN thin layers and Al 0.5 Ga 0.5 N thin layers arranged in a stack, a stack period of the AlN ultra-thin quantum well being less than 5; The gate electrode is a T-shaped gate electrode. AlN thin layer thickness and Al 0.5 Ga 0.5 The ratio between the thickness of N thin layers is 5:3; A rectangular aluminum nitride covering layer is arranged between the T-shaped gate electrode and the aluminum nitride single-crystal barrier layer, wherein the thickness of the rectangular aluminum nitride covering layer is less than the first vertical distance, and the width and length of the rectangular aluminum nitride covering layer are the same as the gate electrode. The substrate comprises a Si substrate and a sapphire substrate.

2. The semiconductor structure having a barrier layer comprising aluminum nitride single crystal according to claim 1, characterized in that, The buffer layer is an AlGaN buffer layer.

3. The semiconductor structure having a barrier layer comprising aluminum nitride single crystal according to claim 1, wherein The method comprises the following steps:

4. A method for growing a semiconductor structure having a barrier layer comprising a single crystal of aluminum nitride as claimed in any one of claims 1 to 3, characterized in that, S1: pretreating the substrate in a MOCVD cavity; S2: growing the buffer layer on the pretreated substrate; S3: adjusting the temperature to 1080℃, the TMG flow rate is 100μmol / min, and the GaN channel layer is grown at a growth rate of 1.2μm / h; S4: growing the aluminum nitride single-crystal barrier layer at a gradient temperature according to the ratio between the first vertical distance and the second vertical distance; S5: adjusting the temperature to 900℃, switching the TMA flow rate and the TMG flow rate according to the periodic stacking rule to grow the AlN ultra-thin quantum wells, wherein the temperature is adjusted to 700℃ in a nitrogen environment for a preset time length at the end of each stacking period for in-situ annealing; S6: growing the remaining thickness of the aluminum nitride single-crystal barrier layer at a gradient temperature; S7: growing the source electrode, the gate electrode and the drain electrode respectively to obtain the semiconductor structure. The S4 specifically comprises the following steps: adjusting the temperature to 850℃ to grow a first preset thickness of the aluminum nitride single-crystal barrier layer; adjusting the temperature to 950℃ to grow a second preset thickness of the aluminum nitride single-crystal barrier layer, wherein the ratio between the first preset thickness and the second preset thickness is 1:

6.

5. The method for growing a semiconductor structure having a barrier layer comprising a single crystal of aluminum nitride according to claim 4, characterized in that, The post-processing technology of the aluminum nitride single-crystal barrier layer comprises the following step: annealing the aluminum nitride single-crystal barrier layer at 1400℃ in a nitrogen environment.

6. The method for growing a semiconductor structure having a barrier layer comprising a single crystal of aluminum nitride according to claim 5, characterized in that, ​

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